Methods and devices of the aforementioned type are usually used to obtain information about an operating state of the valve. Particularly important changes in the operating state, for example a transition from an open state to a closed state, are derivable from extremes of a time characteristic of the auxiliary variable, at least in some operating modes or operating points of conventional injectors.
However, the evaluation accuracy of conventional methods is often insufficient, in particular in the event of short activation times and/or minimal valve lifts.